Triethylene and tetraethylene glycol diamines may be continuously produced from glycols catalytically. The triethylene glycol diamine and tetraethylene glycol diamine products are known under the trade names JEFFAMINE.RTM. EDR-148 Amine and JEFFAMINE.RTM. EDR-192 Amine, respectively, as made by Texaco Chemical Co. These materials are useful as epoxy curing agents.
It is, of course, known to react materials having primary amine groups, with compounds having carboxylic acid groups.
Of particular interest is U.S. Pat. No. 2,359,867 which teaches polymers having a high receptivity for acid dyes, which polymers are the reaction product of 75 to 95 parts by weight of a mixture of hexamethylenediamine and adipic acid in substantially equal proportions, and 5 to 25 parts by weight of a polyamide-forming composition selected from the class of (a) mixtures of diamine and dibasic carboxylic acid in substantially equimolecular proportions, and (b) monoaminomonocarboxylic acids. The polyamide-forming composition has a bifunctional polyamide-forming reactant containing at least one oxygen atom in the chain of atoms separating its amide-forming groups. Such polyamide forming reaction may include compounds of the formula NH.sub.2 --(CH.sub.2 CH.sub.2 O).sub.x --CH.sub.2 CH.sub.2 --NH.sub.2, where x ranges from 2 to 3. Also of interest is S. Iwabuchi, et al., "Darstellung und Eigenschaften von Copolyamiden mit Oxyethylenegruppen in definierter Sequenz," Makromol. Chem., Vol. 183, (1982) pp. 1427-1433. The summary to the article indicates that polyamides of the formula: ##STR1## were synthesized from .alpha.,.omega.-diamino-substituted oligo(oxyethylene)s and bis-chlorides of dicarboxylic acids. The copolymers contained up to five oxyethylene units per repeating unit, and properties like solubility, thermal stability and complexing ability towards alkali metal cations were influenced.
A crystalline polyamide which has improved tensile strength and which has a heat deflection temperature in excess of 240.degree. C. when filled is formed from dicarboxylic acid compounds comprising compounds of terephthalic acid and isophthalic acid in a molar ratio of at least 80:20 to about 99:1 and diamines comprising hexamethylene diamine and trimethylhexamethylene diamine in a molar ratio of about 98:2 to about 60:40, according to U.S. Pat. No. 4,617,342.
These kinds of materials may be used for hot melt adhesives. For example, U.S. Pat. No. 4,656,242 describes that poly(ester-amide) polymers made from an acid component and a substantially equivalent amount of an amine and a diol component are suitable as hot melt adhesives for bonding plastics. The acid component has 10-80 equivalent percent of a dimer acid having about 36 carbon atoms and 40-90 equivalent percent of a linear dicarboxylic acid. The amine and diol component has from 40-90 equivalent percent of an organic diamine and 10-60 equivalent percent of a diol. Also of interest is U.S. Pat. No. 4,611,051 which teaches poly(esteramide) hot-melt adhesives prepared from condensation of a mixture of polymeric fatty acids and 1,18-octadecanedicarboxylic acid, and a substantially equivalent proportion of a mixture of a polyamine and a polyol. Suitable polyamines include ethylenediamine, 1,3-propanediamine, 1,4-butanediamine, 1,6-hexamethylene-diamine, piperazine, and 4,4'-methylene-bis-(cyclohexylamine). Appropriate diols are ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexamethylenediol, cyclohexanemethanol, polyethylene glycol and polybutylene glycol.
See also Chemical Abstracts, Vol. 31: 769 9 (1946) reporting Great Britain Patent 562,370 which describes a mixture of at least two preformed synthetic linear polyamides heated in the molten state at amide-forming temperatures until a homogeneous melt blend was obtained. At least one of the polyamides should be soluble in water and the other insoluble. The insoluble polyamide may be polyhexamethylene adipamide. The soluble polyamide may be one in which heteroatoms of oxygen or sulfur are present in the main polyamide chain, such as polytriglycol adipamide and N-methylpolytriglycol adipamide. The resultant polyamides had increased water-absorption properties and improved physical properties.
A good, general background article about some of these amide materials is J. R. Flesher, Jr., "Polyether Block Amide: High-Performance TPE," Modern Plastics, September, 1987, pp. 100-110, where the family of engineering-grade thermoplastic elastomers based on block copolymers of polyethers and polyamides is discussed.
Although polyamides have been incrementally improved as shown by the publications discussed above as examples, there remains a need for new polyamides having improved water absorbancy, but which retain the beneficial properties of polyamides.